According to various weather sources (World Meterological Organization, NOAA, Farmer's Almanac, etc.), it appears that we are in for a weak to
moderate El Nino pattern for this upcoming winter 2012 / 2013.
We had our first freeze out here in west Texas this morning, which is a bit early for this area (by about 3 weeks), so I started to research and found
that the El Nino warmth in the Pacific is in place.
How do El Nino conditions affect the world?
Past El Niño events during the northern hemisphere autumn and winter have been associated, among others, with drier than normal conditions in
parts of Australia, Indonesia, the Philippines, northeastern Brazil, southeastern Africa and parts of Asia.
Wetter than normal conditions have, in the past, tended to be experienced in Ecuador and northern Peru, as well as southern Brazil to central
Argentina and parts of eastern Africa. El Niño winters tend to be mild over western Canada and parts of the northern United States, and wet over the
southern United States.
Source listed above.
Here it is in a visual for the United States:
And for North America and Europe:
Note the above image shows what is known as the Arctic Oscillation. Naturally, there is more than one ocean, so there is more than one effect on our
winter weather outlook. In fact, there is a multitude of factors to consider when trying to judge what the weather is going to do.
However, we also have the NAO, or North Atlantic Oscillation, which operates in tandem with the Arctic Oscillation:
The NAO or North Atlantic Oscillation is simply a "blocking" pattern that allows for cold air to slow down and allows LOW pressure to form off
the coast and has time to explode into snowstorms.
It's basically the traffic cop of weather. Slow the pattern down and the odds of a juiced up system getting into the Eastern Part of the U.S. starts
to increase. Negative NAO = More storm chances east of the Mississippi River.
It appears that we are going to be a bit colder this winter, with increased precipitation, due to the negative AO:
The AO has a positive and negative phase, and is closely related to the NAO. It is not common for the NAO and AO to both be in the same phase at
the same time. In the positive phase, the polar vortex that holds cold air up in the Arctic is strengthened, and the cold air is locked up north.
However, in the negative phase, this vortex weakens, and the cold air is unleashed south into the US.
It’s no coincidence that the regional-scale air pressure patterns linked to the North Atlantic Oscillation are visible in the same maps used to
illustrate the Arctic Oscillation. The similarity makes sense: many meteorologists consider the North Atlantic Oscillation to be a “regional
subset” of the Arctic Oscillation, which operates across the whole Northern Hemisphere.
The east coast of the US could have some whopper snow storms. The southern tier of the US will be wetter than normal.
The US and Canada are in for a real battle this autumn.
Think of it as a battle of the heavyweights. In the north corner of the ring, it’s the Arctic Oscillation. Its punishing blows can knock you out
cold. In the west corner lurks the El Niño. Don’t let the name, which means “little boy”, fool you. He can come roaring out with a cold punch
to the South and hot and heavy in the North.
The El Niño is weak but may pack a warm punch later.
Oh, and just to make the battle even more interesting – in the east corner is the hot Atlantic. This battler has been the past champion, dominating
the ring, baking the US with scorching hot temperatures. The champion is not going to give up easily.
On Saturday, September 22, the opening bell rang and autumn starts. The battle to see which forces shape this fall’s weather will begin. In short,
the hot dry summer is finally dragging to a close and a stormier fall is about to begin.
Let’s pretend that there is a ringside announcer. He is sizing up Round 1 – the opening week of autumn.
The Champion, the hot Atlantic still controls the ring. The US is still warm and dry, but it looks like he is getting tired. Some cooler temperatures
are entering the South.
The cold Arctic Oscillation is entering the ring. Those winds that trap polar air north are weakening and some cooler air is surging into the Great
Lakes and the Midwest. Already we are seeing snowflakes over the Great Lakes. The AO won’t do much this round, but he is shaping up to be a real
contender. This winter will be colder than last winter.
There are some weather forecasters who are forecasting a "negative ENSO" pattern (neither El Nino or La Nina...La Nina is the pattern we had last
year, the cause of much of the drought in the US), but I'm leaning towards a weak El Nino, based on my own observations of an early freeze this far
south, and the decent amount of rain we've been getting of late.
The worst part of the El Nino scenario is the wet weather in California, which is always a precursor to landslides due to burned-out hillsides, and a
glut of snow in the northeastern US. Colder air also means higher utility costs.
But weather is a fickle thing, and forecasting it is difficult. However, this is what the weather blogs and sites are predicting. Better have a
little extra food and water stored, just in case things get crazy.